A disk drive, such as a magnetic disk drive, comprises a magnetic disk, spindle motor, magnetic head, and carriage assembly. The magnetic disk is disposed in a case. The spindle motor supports and rotates the magnetic disk. The magnetic head reads data from and writes data to the magnetic disk. The carriage assembly supports the magnetic head for movement relative to the magnetic disk. The carriage assembly includes a rotatable arm, and a suspension extending from the arm. The magnetic head is supported on the extended end of the suspension. The magnetic head includes a slider attached to the suspension, and a head section on the slider. The head section comprises a recording head for writing and a read head for reading.
Magnetic heads for perpendicular magnetic recording have recently been proposed in order to increase the recording density and capacity of a magnetic disk drive or reduce its size. In one such magnetic head, a recording head comprises a main pole configured to produce a perpendicular magnetic field, trailing shield, and coil. The trailing shield is located on the trailing side of the main pole with a write gap therebetween and configured to close a magnetic path that leads to the magnetic disk. The coil serves to pass magnetic flux through the main pole.
A magnetic head based on high-frequency field assist recording is proposed in which a high-frequency oscillator is disposed between a main pole and an end portion of a trailing shield on the recoding medium side, and an electric current is applied to the high-frequency oscillator through the main pole and trailing shield.
When an electric current is flowed from the main pole to the trailing shield, disturbance of a magnetic domain in the main pole can be eliminated, an efficient magnetic path can be led, and a magnetic field generated from an end of the main pole is intensified. However, in such a head configuration, a large return magnetic field is also generated immediately below the trailing shield arranged at the trailing end of the main pole to interpose a small gap therebetween, thereby resulting in a problem that erasing or deterioration of a recorded signal occurs.